Machine for grinding tracers and tools for engraving-machines.



PATENTED AUG. 11,1903.

M. BARR. MACHINE FOR GRINDING TRAGERS AND TOOLS FOR ENGRAVING MACHINES.

APPLICATION FILED 00113. 1900.

3 SHBETS-SHEET 1.

No. 736,193 PATBNTED AUG. 11, 1963.

- M. BARR. V MACHINE FOR GRINDING TRAOERS AND TOOLS FOR ENGRAVING MACHINES.

APPLICATION FILED OCT. 13. 1900.

3 SHEETS-SHEET 2- Zimm- TNE mums PETERS or) mow-Una. wasuma'rom o. c

No. 733,193. PATENTED 'AUG. 11,1903.

M. BARR.

MAGHINILFOR GRINDING TRAOERS AND TOOLS POR'ENGRAVING MACHINES.

. APPLICATION FILED 00113. I900.

H0 MODEL.

. sarily a finitev thickness the pattern will be" UNITED STAT Es iatented Augustdl, IQOL'di "ATENT OFFICE.

MARK BARR,

OF BROADHEATI-I, ENGLAND, ASSIGNOR TO THE LINOTYPE COMPANY, LIMITED, OF LONDON, ENGLAND.

MACHINE For GRINDING TRACE-IRS AND TOOLS For ENGRAViNG-MACHINES srncrmcn'rxon formingpart of Letters Patent No. 736,193, dated August 11, 1905.

Application filed OctoberlS, 1 900. $erial No. 32.999. (N0 model.)

To aZZ whom it may concern:

Be it'known that I, MARK BARR, of the LinotypeWorks, Broadheath, in the county of Chester, England, have invented certain new and useful Improvements in Machines for Grinding Tracers and Tools for Engraving-Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

The present invention consists, first, in improvements in the relationship between the tracer ends and the cutting-tools of engraving-machines, and, secondly, in grinding-machines for grinding such tools. It enables the form of the tracer end to control the form of the cutting-tool which itis to guide in the en graving-machine of which each is an organ, such control being exercised by means of the improved grinding-machine.

In an engraving -macl1ine-such, for instance, as the well-known Benton Waldo or the Ballou engraving-machine-for producing objects which, like dies, have three dimensionslength', width, and depth of designit is essential thatthe cutting edges of the tool shall have the same form as the tracer end, the dimensions of those edges being at the same time modified according to the desired ratio between pattern and obj ect. In all such engraving-machines it is themotion of the axis of the tracer end which is transmitted to and reproduced proportionally and with more orlcss accuracy in the axis of the tool; but as the tracer end has necestouched, as the said end is moved over it, by points in the surface of the tracer end which are radially on one side of the axis of that end. Consequently, it is the motions of those points as distinguished from'the motions of points situated in the said axis and in the same horizontal plane that are reproduced in homologous points in the surface of the tool.

Now I am convinced that the principles laid down in the preceding paragraph have not been appreciated hitherto at their truevalue or have not been carried into effect.

' An engraving-machine is called upon to produce objects in many ratios that has hitherto necessitated an indefinitely large number of tools, so as to be ready for an object in any ratio to the pattern. Further, as it is impracticable to grind a toolheldin any headstock other than the one in which it is to be pointed, and sharp. These ends are for trac ing over any pattern which may be brought to the engraving-machineto be worked from, and for each ratio between pattern and object corresponding tools are ground, that grinding being effected in the improved grinding-ma chine described farther on.

The present invention requires that the form (using this word as including all the geometric elements) of each of the tracer ends mentioned in the preceding paragraph shall be one that is easily expressed by one or more simple elements or coordinates, and, further, that the movements of the tool-blank-that is, the unground toolin front of the abrading member of the grinding-machine shall be con trolled by adjustable devices the adjusted positions of which correspond with the geomettric elements of the tracer end. The result is that as these geometric elementswill be known to the operator the mere adjustment of the said devices-leads forthwith to the generation of a tool having corresponding form or geometric elements.

The above-mentioned simple elements or coordinates appear first in the tracer end, to

be afterward reproducedin the tool. The

easiest process forgiving the desired form to a tracer end is well-known to users of engraving-machines to be of one grinding, the

i unground end being held up to the grinder at right angles with its surface and rocked about a center of oscillation situated somewhere along the axis of the tracer end or to one side thereof. Now the radius (R) of the curva ture of the ground end and the distance (D) of the center of oscillation from the axis of the tracer end are the two simple elements or coordinates above mentioned, and their respective dimensions settle the form of the tracer end. Both range from zero upward. If R be infinite and D be zero, there will not be any curvature at all. If R equal the radius of the cross-section of the unformed tracer end and D be zero, the form of that end will be hemispherical, and it will acquire acuteness in proportion as D is made longer. All the tracer ends are, according to the present invention, bodies of revolution-i. 6., any section at right angles with the axis is exactly circularand each one is, for the purpose of the invention, marked with the respective values of R and D. Several sizes of each form of tracer end are provided.

The machine for grinding a tool is of the same construction exactly as the one for grinding the tracer end and with which it is homologous, but correspondingly smaller. The relationship between the tracer end and its homologous tool can be realized with a tracer end formed by any convenient means;

' but seeing that the R and D of the tracer end must be known before it can be formed the desired form can be obtained more quicklyby the improved machine than by any means hitherto used.

The following description of the figures treats them as if the machine illustrated is a small onethat is, one for grinding a tool.

Referring to the accompanying drawings, which are to be taken as part of this specification and-read therewith, Figure 1 is a plan of the improved grinding-machine; Fi 2, a front elevation, partly in section and corresponding therewith; Fig. 3, a side elevation of Fig. 1 from the lefthand, and Fig. 4 a side elevation of Fig. 1 from the right hand.

A suitable base A carries a pair of bearings 13 O, in which turns a tube D, containing a cylindrical abrader E. The flat end E of the latter, projecting beyond the front end of they said tube D, is the abrading member already referred to.

D is the driving-pulley for the tube D. A diamond dresser F to dress up the surface E is mounted on a suitable traverser G, adapted to work in a traverser-block G, fast on the base A. The traversing is effected by aleatherfriction-wheelll, adapted to be moved diametrically across the rear end of the tube D and which end has a leather facing 61 to prevent the wheel H slipping. The frictionwheel H is mounted upon theend of a shaft I, turning in bearings J J.

K is the traverser-screw, turning in a nut L and carrying a worm-wheel M on its outer end, which wheel engages with a worm N on the shaft 0, the two shafts O and I being geared together by a worm-wheel P and worm Q. The engagement of the friction-wheel II with the facing d on the rear end of the tube D on one s ide of the axis of the latter moves facing 61 on one side of the axis of the tubeD to respectively traversethe dresser F across the surface E to dress it and to return the said dresser to its original position or to hold it out of engagement with the said facing when the dresser F 'is to remain out of action. This last position is theone illustrated in Fig. 1. To allow of the shaft I being so slid to and fro without disengaging the worm Q and the wheel P, the former is mounted upon a sleeve Q, through which the shaft I is passed; The engagement of the Worm Q with the wheel P and the adjacent bearing J in part prevent the said sleeve moving longitudinally with the shaft I, while the engagement of the feather q,-fast on the sleeve Q in a slot q in the shaft 1, provides for the latter carrying the said sleeve around with it.

The abrader 'E is provided with any suitable means, such as a set-screw e, to set it up toward the front to compensate for wear. The length of the traverse of the traverser G in the block G is limited in both direct-ions by the projection of aset-screw fast in-the said block, into a slot g in the traverser G. The diamond dresser F is capable of being set up to the face E of the abrader by the following means. It is adapted to slide in a suitable guide in the traverser G. I

g is a setting-up screw parallel with the dresser F and engaging in the traverser G as in a nut, and g is a milled head on the outer end of it. It engages with the dresser F to set it up to the face E or to withdraw it by a collar 9 which fits in an annular groove q in the said dresser.

S is a slide capable of a reciprocating linear motion between guides s s on the base A to and from the surface E. The limit of the motion of the slide S up to the said surface E is decided by a stop-block T, sliding in guides This block T carries a bracket U, which overhangs the slide S and is fitted with a conical plug V, which can hold the slide S to the stop-block T by being forced down one side of a conical hole in the said slide S by a screw 1;. To enable it to do that, the screw 1; works in the stop-block T, as shown best in Fig. 3, and has a collar o fast on it and engaging in an annular groove '0 in the plug V.

The steel rod from which the tool end W is to be made is carried in the usual quillX and clamp X.

X is a disk fast on the outer end of the quill X and having four notches X in its periphery, into each of which the spring-detent X can engage to hold the face of the tool end W, then being ground, steady, as is usual in machines of this class. The clamp X stands up from a slide 40, working in a table 0c,which is IIO pivoted in the slide S by a hollow pivot 40', fast to it and turning in a bearing 00 inthe said slide, as shown best in Fig. 2. The distance of the axis of this pivot 00 from the surface E is in allcases proportional to the geometric element R already described.

The pin a is of known diameter-say, 6. q., two-tenths of an inch. If the radius to which the tool isto be ground is also twotenths of an inch, the stop-block T, clamped to the base A, servesas a stop for the slide S so long as the radius just mentioned is the desired tool radius and the micrometer T is not called into action; but other tool radii mayor will be required, and to obviate the necessity of providing a pin for each radius I equip the machine with the micrometer T in order that the radius of the pin x maybe transferred to its ram through. the slide S and the stop T. WVhen this transference has been eifected it is obvious that the micrometer can be set for any other radius less or more than that of the pin :0 and that its ram, instead of the stop T,

which the slide S abuts in sucha manner that with reference to the surface E.

the said slide shall have a definite position The hollow pivot 96 has a tapered and axial hole into which fits a circular pin 03 having an upper ried by the base A.

parallel part of a known diameter. To determine the position of the slide S the pin is inserted in the hollow pivot 00, the stopblock T and slide S made fast together by the conical plug V, and the slide S moved up toward the grinding-surface E until the parallel portion 00 of the pin 00 bears against it. The stop-block T is then clamped to the base A in its new position by a suitable clamp 15. Behind the stop-block T there is a micrometer-screw T in a clamping-sleeve T car- This micrometer-screw T is set to the reading which is equal to the radius of the parallel portion m of the pin :0 and the barrel of the said micrometer is then pushed through the sleeve T up to the stopblock T and clamped in that vposition. The stop-block T is next unclamped from the base A, disconnected from the slide S, and the pin x taken out ofthe hollow pivot 5c. The micrometer reading gives the exact distance that This'distance is proportional to the element D already described. w is a set-screw for holding the slide w in its adjusted position.

shall be, for instance, a tenth of the tracer end, having the elements R and D, the readings of the micrometers T w are not set to one-tenth R and one-tenth D, respectively, but to such values as will give the elements one-tenth R and one-tenth D to the tool edges. Now when a tool with alternate flats and edges is at work the sides of the hole or of the gutter which it cuts have a radius less than that of the faces. So, either graphically or mathematically, the corresponding radii of faces and edges are determined for each type of tracer end, and the distance of the axis of the hollow pivot 00 from the axis of the tool corresponding to the radius of face curvature is found in the same way. Both these modified elements R and D are then marked on the respective tracer ends, so that the setting of the two micrometers T w of the improved grinding-machine to readings proportional, according to the ratio of reduction, to those elements so marked adapts the machine to grind the end of the steel rod then in the quill X into a tool the form of whose cutting edges corresponds proportionally (and more or less approximately) to the form of the tracer end.

1. In a grindingmachine, the combination of a slide adapted to slide to and from the abrading member, to pivot about a hollow pivot on the base of the machine and to receive a pin of a known diameter with its axis alined with that of the pivot; a slide adjustable on the base of the machine to serve as a stop for the first-mentioned slide; a supplementary slide to carry the rod to be ground and to slide in the first-mentioned slide in the direction of the latters motion on-the niachine-base, and a micrometer carried by the first-mentioned slide and adapted to control the position of the supplementary slide thereupon.

2. Ina grinding-machine, the combination of a slide adapted to slide to and from the abrading member and to pivot about a hollow pivot on the base of the machine; a hollow pivot in the said slide adapted to receive a pin of a known diameter; a slide adapted to serve as a stop for the first-mentioned slide and having a clamp by which it can be temporarily held to the machine-base; a clamp by which both the said slides can be temporarily held together; a supplementary slide to carry the rod to be ground and adapted to slide in the first-mentioned slide in the direction of the latters motion on the machine-base, and a micrometer carried by the first-mentioned slide and adapted to control the position of the supplementary slide thereupon.

3. In a grinding-machine, the combination of a slide adapted toslide to and from the abrading member and to pivot about a hollow pivot on the base of the machine; a hollow pivot in the said slide adapted to receive a pin of aknown diameter; a slide adapted to serve as a stop for the first-mentioned slide and having a clamp by which it can be temporarily held to the machine-base; a clamp by which both the said slides can be temporarily held together; a micrometer working in a clamp- MARK BARR.

Witnesses:

HORACE GRELLIER, G. F. WARREN. 

